[ RadSafe ] AW: How much of RSH still exists?

[Rainer.Facius at dlr.de]

Ludwig:

 

You most appropriately remark "this paper ... does not give the cancer
incidences in the various dose groups."

 

The Cardis BMJ 2005 paper is essentially an extended abstract if you
relate it to the amount of data that it comprises. 

 

Unfortunately, in some recent epidemiologic studies the journal editors
allowed the authors to present only the values of fit parameters and
model statistics without the tables displaying the raw numbers. In all
larger worker studies where these raw numbers had been presented, i.e.,
in each dose category the number of observed and the number of expected
cases of a given cancer (or disease), these data are perfectly
compatible with a "no-effect" model in the dose ranges given. 

 

Hopefully, the journal editors where by the end of this or the beginning
of the next year the full papers of the Cardis study will be published
will insist that these raw data are presented too. Otherwise it will be
impossible to critically evaluate these papers, which in turn is
equivalent to these papers being a wasted effort - to print them and to
read them.

 

It might be well worth the effort that those who know where these papers
have been submitted contact the journal editors with respect to the
presentation of raw data.

 

Best regards, Rainer

 
Dr. Rainer Facius
German Aerospace Center
Institute of Aerospace Medicine
Linder Hoehe
51147 Koeln
GERMANY
Voice: +49 2203 601 3147 or 3150
FAX:   +49 2203 61970
 

________________________________

Von: owner-rad-sci-l at WPI.EDU [mailto:owner-rad-sci-l at WPI.EDU] Im Auftrag
von Ludwig E. Feinendegen
Gesendet: Montag, 19. September 2005 12:52
An: Don Higson; Jim Muckerheide, RSH; Stanley E. Logan
Betreff: Re: How much of RSH still exists?


Friends:
 
The Cardis et al paper is impresive becuse it handles large numbers.
However, the analysis of the data in this paper applies a linear
dose-risk function and does not give the cancer incidences in the
various dose groups. The enormous spread of calculated risk coefficients
in the various cohorts in addition to the application of a linear
function in the data analysis limits the power of this paper to address
the low-dose cancer risk.
 
Some quotations from the Cardis et al.paper: 
A total of 24 158 (5.9%) people were known to have died during the study
period: 6519 from cancers other than leukaemia and 196 from leukaemia
excluding chronic lymphocytic leukaemia. --- The distribution of
recorded doses was skewed (fig 1). Ninety per cent of workers received
cumulative doses < 50 mSv and less than 0.1% received cumulative doses >
500 mSv. --- Analyses were based on a linear relative risk Poisson
regression model, in which the relative risk is of the form 1+Z, where Z
is the cumulative dose equivalent in Sv and is the excess relative risk
per Sv; ---  Attributable risks were estimated by multiplying the excess
relative risks by the average dose in the cohort. ---  Only when we
excluded Canada was the excess relative risk no longer significantly
different from zero (0.58, - 0.22 to 1.55).--- Overall, on the basis of
our central risk estimates, we estimate that 1-2% of deaths from cancer
(including leukaemia) among workers in this cohort may be attributable
to radiation.

Best regards,

Ludwig